The rate of thermal exchange between a person and the environment is dependent upon a number of factors, such as activity level, the nature and condition of the environment, and the characteristics of the clothing (such as a shoe) having contact with the wearer's skin. The transfer of body heat from the skin through clothing or footwear to the environment takes place by conduction, convection, radiation and evaporation, the physiological details and mechanisms of which are generally well known.
In clothing (i.e., footwear), conduction or convection from the body through the clothing to the environment is the main mode of heat loss from the body to the outer surface of clothing. Thermal energy is principally transferred by conduction through the clothing, and is thereafter transferred by conduction or convection as well as radiation from the clothing to the environment. Given the propensity for the extremities to easily become cold, it would therefore be of commercial value to improve the insulating capacity of clothing.
In addition to the foregoing, many commodities and products are sensitive to changes in temperature. Providing an isothermal environment or preventing temperature extremes during shipment would thus enhance or maintain the condition of the product upon delivery to the retailer or the consumer. For example, fresh produce must be maintained at constant temperature or it will wilt. In extreme cases the produce can spoil. Likewise, fresh plants should be maintained within narrow temperature and humidity ranges during transport in order to assure delivery in prime condition. Transportation via truck and/or train may subject the shipped product to wide swings in temperature. For example, in a cross-country shipment, the product may be subject to high desert temperatures during the day and cooler temperatures at night. In addition, the fact that the product is shipped in a closed metal container may exacerbate the total temperature swing. It would therefore be of commercial value if the temperature within shipping containers could be maintained at a constant level. In addition, in other circumstances, it would also be of commercial value if the total temperature swing could be reduced.
The automobile is another area which would benefit from the creation of a more nearly isothermal environment. For example, it is well known that in the summer when a car is parked in the sun, the temperature can rise very quickly to well over 120 degrees fahrenheit. This rapid rise in temperature can cause considerable inconvenience to the owner of the vehicle by having to cool down the passenger compartment of the vehicle, can injure pets that may be left in the vehicle, and will accelerate wear and tear on the interior of the vehicle.
It is, therefore, an object of the present invention to provide an improved thermal management system.
It is another object of the present invention to provide a thermal control material which assists in maintaining an isothermal environment.
It is, therefore, an object of the present invention to provide clothing (i.e., a shoe insole) having enhanced ability to insulate the wearer (foot) from hot or cold.
Yet another object of the present invention is to provide a thermal control material with enhanced insulating properties that also has a high degree of structural integrity.
A still further object of the present invention is to provide a thermal control material having enhanced thermal storage properties that is reusable.